说明：  AT89s51单片机8位流水灯逐个点亮再逐个息灭、4位数码管全亮显示、喇叭发声、键盘扫描的汇编源程序
(8-bit single-chip AT89s51 water lit by lights out and then by income, four full-bright LED display, audible horn, keyboard scan source code compilation)